The human interleukin-2 receptor is being studied to understand specific critical components of the T cell immune response in normal and neoplastic cells. We have significantly progressed in our study of (1) biochemical analysis of high, intermediate, and low affinity human and murine IL2Rs; (2) characterization of transcription regulatory sequences in the IL2 receptor alpha chain gene (3) the characterization of the transcription regulatory sequences in the IL-2 receptor beta chain gene; (4) the expression of the lL-2R alpha and beta chain cDNAs in various target cell types to assist in elucidating IL-2 mediated signal transduction. In addition, we have significantly progressed in our study of the Act-2 cytokine. We have (1) characterized the gene encoding the Act-2 cytokine and 2) the characterized cellular receptors for the Act-2 cytokine as a prelude to potentially cloning the Act-2 receptor.